Tacrolimus for prevention of graft-versus-host disease after mismatched unrelated donor cord blood transplantation

Ten children with hematologic malignancies or a storage disease underwent transplantation using cord blood cells from an unrelated donor mismatched for 1 (n = 7) or 2 (n = 3) HLA antigens. The median total nucleated cell dose was 4.0 (range, 2.2–7.1) × 107/kg. GVHD prophylaxis consisted of tacrolimus dose-adjusted to maintain a whole blood level of 5–15 ng/ml with or without methotrexate 5 mg/m2 i.v. on days 1, 3, 6 and 11. Corticosteroids were not administered prophylactically. Median follow-up is 12 months (range, 5–28 months). One patient had autologous recovery and subsequently relapsed 153 days post transplant. For the remainder of the patients, the median time to an ANC >0.5 × 109/l was 21 days (range, 19–38 days), and the median time to platelets >20 × 109/l was 39 days (range, 21–97 days). The actuarial risk of grade 2 GVHD was 77% (95% CI, 49–100%), and no patient had grades 3–4 GVHD. Two patients developed chronic GVHD. The survival rate is 90% (95% CI, 81–100%). The combination of tacrolimus and minidose methotrexate is active for the prevention of severe but not moderate acute GVHD after mismatched unrelated donor cord blood transplantation.